*{
    margin: 0;
    padding: 0;
}
.footer{
    position: fixed;
    left: 0;
    bottom: 0;
    height: 50px;
    width: 100%;
    display: flex;
    .footer-item{
        flex-grow: 1;
        height: 50px;
        line-height: 50px;
        text-align: center;
        font-size: 14px;
        &.active{
            background-color: red;
        }
    }
}